Turbine with improved sound reduction

ABSTRACT

The present disclosure generally relates to a turbine for a fluid delivery system and more specifically, but not by limitation, to a portable air turbine for a fluid delivery system having improved sound reduction. In one exemplary embodiment, a portable turbine apparatus is provided and includes a motor and a turbine configured to be driven by the motor for providing pressurized air to an outlet. A first inlet airflow path delivers air to the motor. A first silencer component having sound absorptive material is positioned along the first inlet airflow path and includes at least one orifice formed therethrough for the first inlet airflow path, the at least one orifice having a cross-sectional area of at least 0.01 square inches. A second inlet airflow path delivers air to the turbine. A second silencer component having sound absorptive material is positioned along the second inlet airflow path and includes at least one orifice formed therethrough for the second inlet airflow path, the at least one orifice having a cross-sectional area of at least 0.01 square inches.

BACKGROUND

The present disclosure generally relates to a turbine for a fluiddelivery system and more specifically, but not by limitation, to aportable air turbine for a fluid delivery system having improved soundreduction.

One example of a fluid delivery system comprises a spray-coating systemhaving a device configured to spray a fluid material (e.g., paint, ink,varnish, texture, etc.) through the air onto a surface. Suchspray-coating systems often include a fluid material source and,depending on the particular configuration or type of system, a motor forproviding pressurized fluid material and/or air to an output nozzle ortip that directs the fluid material in a desired spray pattern. Forexample, some common types of fluid delivery systems employ compressedgas, such as air compressed by an air compressor or propelled by aturbine, to direct and/or atomize fluid material particles onto asurface. Fluid material is provided from the fluid material source usingpressure feed, suction feed, and/or gravity feed mechanisms, forexample.

Air turbines used in fluid delivery systems are often portable and arepositioned within a housing having a handle that allows the apparatus tobe carried by a user, for example. However, despite retention of theapparatus within the housing, the emitted noise level can make itdifficult for a user of the equipment to talk with others and can beaudibly uncomfortable for those who work near the equipment for extendedperiods of time. Further, portable turbines can include weightconsiderations or constraints as they are frequently moved (i.e.,carried by a user) between job sites, for example. Accordingly, a needexists for a quieter turbine having suitable performance and weightcharacteristics.

The discussion above is merely provided for general backgroundinformation and is not intended to be used as an aid in determining thescope of the claimed subject matter.

SUMMARY

The present disclosure generally relates to a turbine for a fluiddelivery system and more specifically, but not by limitation, to aportable turbine for a fluid delivery system having improved soundreduction.

In one exemplary embodiment, a portable turbine apparatus is providedand includes a motor and a turbine configured to be driven by the motorfor providing pressurized air to an outlet. A first inlet airflow pathdelivers air to the motor. A first silencer component having soundabsorptive material is positioned along the first inlet airflow path andincludes at least one orifice formed therethrough for the first inletairflow path, the at least one orifice having a cross-sectional area ofat least 0.01 square inches. A second inlet airflow path delivers air tothe turbine. A second silencer component having sound absorptivematerial is positioned along the second inlet airflow path and includesat least one orifice formed therethrough for the second inlet airflowpath, the at least one orifice having a cross-sectional area of at least0.01 square inches.

In one exemplary embodiment, a portable apparatus is provided andincludes a motor and a first inlet airflow path for delivering air tothe motor. The apparatus also includes a mechanism driven by the motorfor compressing air received from a second inlet airflow path. Thecompressed air is provided to an outlet of the apparatus. The apparatusalso includes a first silencer component positioned along the firstinlet airflow path. At least a portion of the first inlet airflow pathpasses through the first silencer component. The first silencercomponent comprising a first layer that includes sound absorptivematerial and a second layer that includes acoustic barrier material. Theapparatus also includes a second silencer component positioned along thesecond inlet airflow path. At least a portion of the second inletairflow path passes through the second silencer component. The secondsilencer component comprises a first layer that includes soundabsorptive material and a second layer that includes acoustic barriermaterial.

In one exemplary embodiment, a portable turbine apparatus is providedand includes a housing, a motor positioned within the housing, and aturbine positioned within the housing and configured to be driven by themotor for providing compressed air to an outlet. The apparatus alsoincludes a first inlet airflow path from a first side of the housing tothe motor and a second inlet airflow path from a second, opposite sideof the housing to the turbine. A first silencer component having a soundabsorbent material is positioned along the first inlet airflow path anda second silencer component having a sound absorbent material ispositioned along the second inlet airflow path.

These and various other features and advantages will be apparent from areading of the following Detailed Description. This Summary is notintended to identify key features or essential features of the claimedsubject matter, nor is it intended to be used as an aid in determiningthe scope of the claimed subject matter. The claimed subject matter isnot limited to implementations that solve any or all disadvantages notedin the background.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary fluid delivery system.

FIG. 2 is a perspective view of a portable turbine apparatus, under oneembodiment.

FIG. 3 is a cross-sectional view of the portable turbine apparatusillustrated in FIG. 2.

FIG. 4 is a partially exploded perspective view of a portable turbineapparatus, under one embodiment.

FIG. 5 is a perspective view of a silencer component, under oneembodiment.

FIG. 6 is a cross-sectional view of the silencer component illustratedin FIG. 5.

FIG. 7 illustrates a backing plate of the silencer component shown inFIG. 6, under one embodiment.

FIG. 8 illustrates a sound absorptive panel of the silencer componentshown in FIG. 6, under one embodiment.

FIG. 9 illustrates a sidewall panel and a baffle panel of the silencercomponent shown in FIG. 6, under one embodiment.

FIG. 10 is a partially exploded perspective view of a portable turbineapparatus, under one embodiment.

FIG. 11 is a perspective view of a silencer component, under oneembodiment.

FIG. 12 is an end view of the silencer component illustrated in FIG. 11.

FIG. 13 is a cross-sectional view of the silencer component illustratedin FIG. 11.

DETAILED DESCRIPTION

FIG. 1 is a diagram illustrating an exemplary fluid delivery system 100.System 100 includes a spray gun 102 configured to spray fluid materialfrom an output 112 when a trigger 110 is actuated (i.e., pulled). Output112 comprises a nozzle or tip configured to discharge the fluid materialin a desired spray pattern. In one embodiment, the fluid material isentrained in an airflow from spray gun 102. In one particular example,spray gun 102 is configured to atomize the fluid material that issprayed through the air. Examples of fluid materials include, but arenot limited to, primers, inks, paints, varnishes, block fillers,elastomerics, drywall mud, textures, popcorn, and splatter finishes,herbicides, insecticides, and food products, to name a few.

In the illustrated embodiment, fluid delivery system 100 comprises anair-driven system that employs pressurized air provided from an airsource (e.g., air compressed by an air compressor or a turbine) topropel material from output 112. A fluid material source 104 isconfigured to provide fluid material to spray gun 102. Fluid material isprovided from the fluid material source 104 using pressure feed, suctionfeed, and/or gravity feed mechanisms, for example. Material source 104can be mounted to spray gun 102 (e.g., an onboard hopper or container)and/or can be remote from (e.g., not mounted to) spray gun 102. Oneexample of a fluid material container that can be utilized with spraygun 102 is illustrated in commonly assigned U.S. Pat. No. 5,655,714, thecontent of which is hereby incorporated by reference in its entirety.

Air source 106 is configured to provide air to spray gun 102 that isused to atomize and propel the fluid material provided from fluidmaterial source 104. In the embodiment illustrated in FIG. 1, air source106 comprises a portable air turbine apparatus that provides pressurizedair to spray gun 102 through a tube 107.

FIG. 2 is a perspective view of one embodiment of a portable air turbineassembly 200 for use in a fluid delivery system, such as system 100illustrated in FIG. 1. Turbine assembly 200 includes a handle 202connected to a turbine housing 204. Turbine housing 204 houses a motorconfigured to drive a turbine that provides a source of pressurized airto an air outlet 206. It is noted that turbine assembly 200 can includemultiple motors and/or multiple turbines. In one embodiment, air outlet206 is connected via an air hose (not shown) to a hand-held paint spraygun, such as an HVLP type spray gun, which uses air to atomize paint.

Turbine assembly 200 includes a first air intake assembly 208 at a firstend 210 of turbine housing 204 and a second air intake assembly 212 at asecond, opposite end 214 of housing 204. Air intake assembly 208provides a first inlet airflow path that delivers air to be compressedby the turbine in housing 204. Air intake assembly 212 provides a secondinlet airflow path that delivers air for cooling the motor in housing204.

FIG. 3 is a cross-sectional view of turbine assembly 200 taken at line3-3 illustrated in FIG. 2. As shown, the first inlet airflow path(generally illustrated by arrow 308) provided from air intake assembly208 is provided to an input 311 of turbine 310. Turbine 310 compressesthe air, which is then delivered to air outlet 206 (illustrated in FIG.2). The second inlet airflow path (generally illustrated by arrow 312)provided from air intake assembly 212 is provided to an input 315 ofmotor 314 to aid in cooling motor 314.

A first air filter assembly 320 is provided in the first inlet airflowpath between end 210 and turbine 310. A second air filter assembly 322is provided in the second inlet airflow path between end 214 and motor314.

In accordance with one embodiment, turbine assembly 200 includes a firstsilencer component 324 positioned along the first inlet airflow path anda second silencer component 326 positioned along the second inletairflow path. Silencer components 324 and 326 are configured to allowthe inlet airflows 308 and 312 while providing sound attenuationqualities. In one embodiment, silencer component 324 is positionedbetween filter 320 and turbine 310 and silencer component 326 ispositioned between air filter 322 and motor 314.

FIG. 4 is a perspective view of turbine assembly 200, illustrating airintake assembly 208 in exploded view. Intake assembly 208 includes anintake assembly housing 402 that is mounted to turbine housing 204, forexample using fasteners such as screws and/or bolts. An air filterassembly 320 is positioned between an intake assembly cap 404 and intakeassembly housing 402. Air filter assembly 320 illustratively comprises atwo-stage filter having a main filter 408 and a pre-filter 412.Pre-filter 412 comprises a foam or foam-like material, for example, andis configured to filter large particles in the inlet airflow, prior tothe airflow passing through main filter 408.

In one example, pre-filter 412 is easily removable for cleaning and/orreplacement, as desired. Main filter 408 is retained in a filter frame410 and comprises a pleated material (such as paper or paper-likematerials), for example. Main filter 408 has finer filtrationcapabilities as compared to pre-filter 412 and operates to keep some orall particles out of the atomizing air provided by the turbine. In oneembodiment, filter frame 410 is retained within a portion of intakeassembly housing 402 and can comprise a seal (not shown in FIG. 4), suchas an o-ring and the like, positioned between the filter frame 410 andhousing 402.

Silencer component 324 is positioned between intake assembly housing 402and turbine housing 204. A first side 404 of silencer component 324faces air filter assembly 320 and a second side 406 of silencercomponent 324 faces turbine housing 204.

FIG. 5 is a perspective view of silencer component 324 taken from side406. FIG. 6 is a cross-sectional view of silencer component 324 taken atline 6-6, illustrated in FIG. 5. As shown, silencer component 324comprises a multi-layered structure and includes at least one apertureformed therethrough. In one embodiment, the at least one aperture has across-sectional area of at least 0.01 square inches. A first layer 502and a second layer 504 are substantially planar and form an inletorifice 506. Silencer component 324 also includes a sidewall 508 thatforms an outlet 510. Arrow 512 generally illustrates the flow of airthrough silencer component 324 between the inlet 506 and the outlet 510.In one embodiment, the airflow from silencer component 324 enters theturbine input (i.e., input 311 illustrated in FIG. 11), which isgenerally illustrated by dashed box 514. The airflow into the input ofthe turbine is generally illustrated by arrows 516.

Silencer component 324 operates to significantly reduce the amount ofsound emanating from the turbine side (i.e., side 210) of assembly 200without an appreciable change in the airflow through intake assembly 208into the turbine. In one embodiment, at least one layer of silencercomponent 324 comprises sound absorptive material(s) (also referred toas acoustical insulation) configured to absorb the sound (generallyillustrated by arrows 518) emanating from the input of the turbine(generally illustrated by dashed box 514), for example. For instance,layer 504 (which is substantially planar) and/or sidewall 508 can bemade of foam or foam-like material, such as, but not limited to,low-density polyester-based open cell urethane foam and the like. In oneembodiment, layer 504 and/or sidewall 508 are made of material having adensity of approximately two pounds per cubic foot (lbs/ft³).

In one embodiment, at least one layer of silencer component 324comprises an acoustic barrier material. The acoustic barrier materialhas lower sound absorption qualities (as compared to the soundabsorptive material used for layer 504 and/or sidewall 508, for example)and is configured to provide sound barrier and vibration dampeningqualities. For example, in one embodiment silencer component 324comprises a layer 502 (that is substantially planar) that is configuredto absorb and/or deflect at least a portion of the sound that passesthrough layer 504. Layer 502 is also referred to as a backing plate towhich layer 504 is adhered. In one embodiment, layer 502 comprises anacoustic barrier material such as, but not limited to, extrudedelastomeric materials and the like. For example, the acoustic barrierlayer can comprise poly-vinyl-chloride (PVC)/vinyl. In one embodiment,layer 502 is formed of a material having a density of approximately onepound per square foot (lb/ft²).

Silencer component 324 can also include a baffle layer 520 that isattached to layer 504 and allows the airflow 512 to flow throughsilencer component 324 while operating to absorb sound that wouldotherwise emanate through inlet 506. Baffle layer 502 can be formed ofthe same, or substantially similar, material as layer 504.

FIG. 7 illustrates backing plate 502. Backing plate 502 has an outerdiameter 702 and at least one orifice 704 formed therethrough. In oneembodiment, outer diameter 702 is approximately 9.25 inches and orifice704 is centered at a radius 706 from the center of plate 502. In oneembodiment, radius 706 is approximately 3.25 inches.

In one example, orifice 704 is formed by two circular apertures 708spaces apart at an angle 710. In one embodiment, the circular aperture708 each have a diameter of approximately 1 inch and angle 710 comprisesan angle of approximately 22 degrees. In one embodiment, plate 502 has athickness 522 (illustrated in FIG. 6) of approximately 0.1 to 0.2inches.

FIG. 8 illustrates sound absorptive layer 504. An orifice 802 is formedin layer 504 and has a height 804 and a width 806. In one embodiment,height 804 is approximately 3.25 inches and width 806 is approximately2.5 inches. A bottom 808 of orifice 802 is spaced a distance 810 fromthe center 812 of panel 504. In one embodiment, distance 810 isapproximately 0.5 inches. In one embodiment, panel 504 has a thickness524 (illustrated in FIG. 6) of approximately 0.5 inches.

FIG. 9 illustrates sidewall 508 and baffle 520. Sidewall 508 isillustrated in an “unrolled” state. In one embodiment, sidewall 508 isformed of a material that is the same, or substantially similar, topanel 504. Sidewall 508 has a length 902, a width 904, and a thickness906. In one embodiment, length 902 is approximately 26.9 inches, width904 is approximately 2.4 inches and thickness 906 is approximately 0.5inches.

In one embodiment, baffle 520 is formed of material that is removed frompanel 504 to form orifice 802. In this embodiment, baffle 520 has aheight 908, width 910, and thickness 912 that is substantially similarto height 804, width 806 and thickness 524, respectively, illustrated inFIG. 6 and FIG. 8.

Referring to FIG. 6, in one embodiment the height 526 of the orificeformed in panel 502 is substantially similar to the gap 528 formedbetween the bottom surface 530 of baffle 520 and the bottom surface 532of the orifice formed in panel 504.

FIG. 10 is a perspective view of turbine assembly 200 illustrating airintake assembly 212 in exploded view. As shown, air filter assembly 322is positioned between an intake assembly housing 1002 and an intakeassembly cap 1004. In one embodiment, air filter assembly 322 comprisesa two-stage filter including a main filter 1110 and a pre-filter 1112.In one example, pre-filter 1112 comprises a foam or foam-like and can besimilar to pre-filter 412 illustrated in FIG. 4. Pre-filter 1112 isconfigured to filter large particles in the inlet airflow, prior to theairflow passing through main filter 1110. In one example, pre-filter1012 is easily removable for cleaning and/or replacement, as desired.

In one embodiment, filter 1110 is substantially similar to filter 408,illustrated in FIG. 4. In one embodiment, filter 1110 is different thanfilter 408 and can comprise a foam or foam-like material, for example.In one example, filter 1110 is configured to allow a greater airflowrate therethrough and/or lesser particle filtration as compared tofilter 408. In this manner, the airflow rate into the motor side ofassembly 200 can be greater than the airflow rate into the turbine sideof assembly 200.

The second silencer component 326 is positioned between the intakeassembly housing 1002 and the turbine housing 204. Intake assemblyhousing 1002 can be attached to turbine housing 204, for example usingfasteners such as screws and/or bolts. A first side 1006 of silencercomponent 326 faces air filter assembly 322 and a second side 1008 ofsilencer component 326 faces turbine housing 204.

FIG. 11 is a perspective view of silencer component 326. As shown,silencer component 326 comprises a multi-layered structure that includesat least one aperture formed therethrough. In one embodiment, the atleast one aperture has a cross-sectional area of at least 0.01 squareinches. A first layer 1106 and a second layer 1108 are substantiallyplanar and include first and second apertures 1102 and 1104 formedtherethrough. FIG. 12 is an end view of silencer component 326 takenfrom side 1006. FIG. 13 is a cross-sectional view of silencer component326 taken from line 13-13 illustrated in FIG. 12.

Silencer component 326 includes at least one layer of sound absorptivematerial. In the illustrated embodiment, layer 1108 comprises a layer ofsound absorptive material that is adhered to a backing layer 1106. Inone embodiment, layer 1108 is formed of a material that is the same as,or substantially similar to, layer 504 (illustrated in FIGS. 5 and 6)and layer 1106 is formed of a material that is the same as, orsubstantially similar to, layer 502 (illustrated in FIGS. 5 and 6).Component 326 also includes a sidewall 1110. In one embodiment, sidewall1110 is substantially similar to sidewall 508 (illustrated in FIGS. 5and 6).

Referring to FIG. 12, orifice 1102 is formed by two circular apertures1112 spaced apart at an angle 1114 along a radius 1116. In oneembodiment, radius 1116 is approximately 3.25 inches and circularapertures 1112 have a diameter of approximately 1 inch. In oneembodiment, the angle 1114 is approximately 36 degrees and the overalldiameter 1118 of component 326 is approximately 9.25 inches. In oneembodiment, aperture 1104 is substantially similar to and a mirror imageof, aperture 1102.

Referring to FIG. 13, silencer component 326 operates to significantlyreduce the amount of sound emanating from the motor side (i.e., side214) of assembly 200 without an appreciable change in the airflowthrough intake assembly 212 into the motor. As illustrated, sound(generally illustrated by arrows 1308) emanating from the input of motor314 (generally illustrated in FIG. 13 by box 1302) is absorbed bysilencer component 326. The airflow (generally illustrated by arrows1304) enters silencer component 326 through orifices 1102 and 1104. Theairflow (generally illustrated by arrows 1306) then enters the motorinput (generally illustrated by block 1302). As shown, an offset existsbetween the silencer input orifices (i.e., orifices 1102 and 1104) andthe motor input (i.e., box 1302), which acts as a baffle to reduce thesound emanating from the turbine assembly through the intake assembly212.

In one embodiment, thickness 1310 of layer 1106 is substantially similarto thickness 522 of layer 502 and thickness 1312 of layer 1108 issubstantially similar to thickness 524 of layer 504. Further, in oneembodiment sidewall 1110 is substantially similar to sidewall 508.

As mentioned above, in one example turbine assembly 200 is portable(e.g., turbine assembly 200 is carried by a user between job sites). Inaccordance with one embodiment, silencer components 324 and 326 aredesigned to be lightweight (e.g., components 324 and 326 do notsignificantly add to the overall weight of turbine assembly 200,components 324 and 326 comprise a small percentage of the overall weightof assembly 200, etc.), while providing improved sound attentionqualities that significantly reduce the overall noise emanating fromturbine assembly 200. For example, in one embodiment the combined weightof components 324 and 326 is less than approximately 1.25 pounds (lbs).In one embodiment, the combined weight of components 324 and 326 isapproximately 1 pound (lb). In one particular example, components 324and 326 have a weight of approximately 0.53 and 0.5 lbs., respectively.

In one particular embodiment, turbine assembly 200 comprises a 5-stageturbine having an overall weight of approximately 22 lbs. Silencercomponents 324 and 326 comprise approximately 1.03 lbs, which isapproximately 4.7 percent of the overall weight of turbine assembly 200.

It is noted that these are examples of particular illustrativeembodiments of turbine assembly 200 and silencer components 324 and 326,and are not meant to limit the scope of the concepts described herein.

While various embodiments of the invention have been set forth in theforegoing description, together with details of the structure andfunction of various embodiments of the disclosure, this disclosure isillustrative only, and changes may be made in detail, especially inmatters of structure and arrangement of parts within the principles ofthe present disclosure to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed. Forexample, the particular elements may vary depending on the particularapplication for the system or method while maintaining substantially thesame functionality without departing from the scope and spirit of thepresent disclosure and/or the appended claims.

1. A portable turbine apparatus comprising: a motor; a turbineconfigured to be driven by the motor for providing pressurized air to anoutlet; a first inlet airflow path for delivering air to the motor,wherein a first silencer component having sound absorptive material ispositioned along the first inlet airflow path and includes at least oneorifice formed therethrough for the first inlet airflow path, the atleast one orifice having a cross-sectional area of at least 0.01 squareinches; and a second inlet airflow path for delivering air to theturbine, wherein a second silencer component having sound absorptivematerial is positioned along the second inlet airflow path and includesat least one orifice formed therethrough for the second inlet airflowpath, the at least one orifice having a cross-sectional area of at least0.01 square inches.
 2. The portable turbine apparatus of claim 1, andfurther comprising: an air filter positioned in the first inlet airflowand spaced apart from the first silencer component.
 3. The portableturbine apparatus of claim 2, wherein the first silencer component ispositioned between the air filter and the motor.
 4. The portable turbineapparatus of claim 1, and further comprising: an air filter positionedin the second inlet airflow and spaced apart from the second silencercomponent.
 5. The portable turbine apparatus of claim 4, wherein thesecond silencer component is positioned between the air filter and theturbine.
 6. The portable turbine apparatus of claim 1, wherein the firstsilencer component comprises a multi-layered structure that includes atleast first and second layers that are substantially planar.
 7. Theportable turbine apparatus of claim 6, wherein the first silencercomponent comprises a first orifice formed through the first and secondlayers and a second orifice formed through the first and second layers,wherein the first and second orifices are spaced equidistant from acenter of the multi-layered structure.
 8. The portable turbine apparatusof claim 1, wherein the second silencer component comprises amulti-layered structure that includes at least first and second layersthat are substantially planar, wherein the at least one orifice isformed through both the first and second layers.
 9. The portable turbineapparatus of claim 8, and further comprising a baffle positioned over atleast a portion of the at least one orifice formed through the secondsilencer component.
 10. A portable apparatus comprising: a motor; afirst inlet airflow path for delivering air to the motor; a mechanismdriven by the motor for compressing air received from a second inletairflow path, wherein the compressed air is provided to an outlet of theapparatus; a first silencer component positioned along the first inletairflow path, wherein at least a portion of the first inlet airflow pathpasses through the first silencer component, the first silencercomponent comprising a first layer that includes sound absorptivematerial and a second layer that includes acoustic barrier material; anda second silencer component positioned along the second inlet airflowpath, wherein at least a portion of the second inlet airflow path passesthrough the second silencer component, the second silencer componentcomprising a first layer that includes sound absorptive material and asecond layer that includes acoustic barrier material.
 11. The portableapparatus of claim 10, wherein the mechanism comprises an air turbine,the air turbine and motor being enclosed by a turbine housing of theapparatus.
 12. The portable apparatus of claim 10, wherein the firstinlet airflow enters a first side of the turbine housing and the secondinlet airflow enters a second, opposite side of the turbine housing. 13.The portable apparatus of claim 10, wherein the first silencer componentis positioned within a first inlet housing that is removably coupled tothe turbine housing.
 14. The portable apparatus of claim 13, wherein thesecond silencer component is positioned within a second inlet housingthat is removably coupled to the turbine housing.
 15. The portableapparatus of claim 14, wherein each of the first and second silencercomponents comprise multi-layered structures having at least one soundabsorptive material layer attached to a backing layer comprising theacoustic barrier material.
 16. A portable turbine apparatus comprising:a housing; a motor positioned within the housing; a turbine positionedwithin the housing and configured to be driven by the motor forproviding compressed air to an outlet; a first inlet airflow path from afirst side of the housing to the motor and a second inlet airflow pathfrom a second, opposite side of the housing to the turbine; a firstsilencer component having a sound absorbent material positioned alongthe first inlet airflow path; and a second silencer component having asound absorbent material positioned along the second inlet airflow path.17. The portable apparatus of claim 16, wherein the first silencercomponent comprises a multi-layered structure that includes at leastfirst and second layers that are substantially planar.
 18. The portableapparatus of claim 16, wherein the first silencer component comprises afirst orifice formed through the first and second layers and a secondorifice formed through the first and second layers, wherein the firstand second orifices are spaced equidistant from a center of themulti-layered structure.
 19. The portable apparatus of claim 16, whereinthe second silencer component comprises a multi-layered structure thatincludes at least first and second layers that are substantially planar,wherein the at least one orifice is formed through both the first andsecond layers.
 20. The portable apparatus of claim 16, and furthercomprising a baffle positioned over at least a portion of the at leastone orifice formed through the second silencer component.